ELASTOSIL® R plus 4000/60 US
ELASTOSIL® R plus 4000/60 US HCR silicone rubbers are addition-curing, two part compounds (batch grades). The vulcanizates show excellent transparancy and good to very good mechanical properties. Properly postcured vulcanizates of ELASTOSIL® R plus 4000/60 US comply with BfR and FDA food contact regulations. The material also passes USP XXIII Class VI and ISO 10993 certification is available. No peroxide decomposition products are formed during vulcanization. In order to obtain an intermediate hardness, the different durometer grades may be blended with the PT 2 catalyst added last.
ELASTOSIL® R plus 4000/60 US materials are intended for fabrication of molded articles that afford high transparency and very good tear resistance values.
ELASTOSIL® R plus 4000/60 US may not be cured with peroxides, only with the catalyst batch ELASTOSIL® AUX PT2.
ELASTOSIL® R plus 4000/60 US and Curing Agent PT 2 are mixed homogeneously on a roll mill in a ratio of 100 : 1.5. Care must be taken to keep the mill and compound as cool as possible during mixing.
The temperature of the rubber should not exceed 35°C, or risk partial curing and reduced pot life.
Crosslinking begins when Curing Agent PT 2 has been added. The rate and degree of crosslinking depends on the storage time and temperature. At 23°C, the mixture has a pot life of about 6-8 hours. This can be extended by storing the catalyzed mixture at a lower temperature.
The "Best use before end date" of each batch is shown on the Certificate of Analysis. Storage beyond the date specified on the Certificate of Analysis does not necessarily mean that the product is no longer usable. In this case however, the properties required for the intended use must be checked for quality assurance reasons.